Synthesis and evaluation of novel meso-substitutedphenyl dithieno[3,2-b]thiophene-fused BODIPY derivatives as efficient photosensitizers for photodynamic therapy.

The discovery of new photosensitizer drugs with long wavelength Uv–vis absorption, high efficiency and low side-effects is still a challenge in photodynamic therapy. Here a series of novel mes o-substitutedphenyl thieno[3,2-b]thiophene-fused BODIPY derivatives were designed, synthesized and characterized. All these compounds have strong absorption at 640–680 nm and obvious fluorescence emission at 650–760 nm. They exhibited high singlet oxygen generation ability and significant photodynamic efficiency against Eca-109 cancer cells. Compounds II 4 , II 6 , II 9 , II 10 and II 13 could generate intracellular ROS and induce cell apoptosis after laser irradiation, which displayed superior photodynamic efficiency against Eca-109 cells than Temoporfin in vitro and in vivo. Among them, compound II 4 specifically exhibited excellent anti-tumor efficacy, and could be selected as a new drug candidate for PDT. [Display omitted] • A series of novel TT-BODIPY derivatives were designed, synthesized and evaluated. • They exhibited NIR absorptions (650 nm) and high molar extinction coefficients. • They displayed good singlet oxygen generation and anti-tumor (Eca-109) abilities. • Compound II 4 showed much better photodynamic activity than Temoporfin. [ABSTRACT FROM AUTHOR]